The present invention relates to pushbutton assemblies for actuating electrical switches and in particular to bias means for resiliently urging the pushbutton to its normal rest position.
Prior pushbutton assemblies have typically included a pushbutton actuator disposable in an associated housing or receptacle. Typically, some form of bias spring is provided for engaging the pushbutton actuator, resiliently to urge it to a normal rest position. The bias means is frequently in the form of a helical compression spring. This arrangement necessitates an additional part, increasing the cost of manufacture and assembly.
It is known to provide pushbutton assemblies with spring-type bias means which are integral with the pushbutton member. Such integral bias means are disclosed, for example, in U.S. Pat. Nos. 4,218,599, 4,066,860 and 3,808,389. In the '389 patent, the bias means is an annular accordion-pleated member which is quite complicated and expensive to manufacture and which causes high stresses in the plastic material of the bias member. The integral bias members of the other aforementioned patents extend laterally outwardly well beyond the periphery of the pushbutton, and therefore, cannot be used in the standard pushbutton receptacles.